I’m pleased to present Dr. Ramesh Kumar Bhandari, an Electrical Engineer, on this blog as a guest writer. He is from Nepal and currently working as a researcher at a Japanese company that manufactures electronic products. He possesses a Ph.D. degree in Electrical & Electronics Engineering from a Japanese University. He was my classmate as well as the gold-medalist (topper) when we studied Bachelors degree in Electrical Engineering from the Institute of Engineering, Pulchowk Campus, Nepal. I am thankful to Dr. Bhandari for writing this article for the readers of this blog. Please welcome him as he prepares to analyze the viability of solar power system in the Nepalese context.

Nepal's electricity scarcity has worsened so much that it is creating havoc in almost all aspects of our lives. The problem has arisen due to a large gap between the demand and supply. The gap continued to widen over the past years because new generating plants could not be added to the grid despite the demand skyrocketing. A well-written article in this blog by Er. Nava Raj Karki analyzes in detail its causes, as well as proposes possible solutions. Recently, there have been many expert opinions about how we should go ahead in such a situation. Many of these opinions are about exploiting the renewable sources such as wind and solar energies. In this article, I would like to focus on solar photovoltaics (PV) and its relevance in the context of our current electricity problem.

Photovoltaics: Generating electricity from the sunlight

The sunlight, freely available almost everywhere on the Earth, contains on average about 1 kW of energy per m2. It is the main energy source of our earth, which sustains the climate and ecosystem by maintaining temperature, creating rivers and winds, etc. This free energy can also be converted directly into electricity by means of solar PV panels.

In the case of grid-connected solar homes, power is fed (sold) to the grid when there is a surplus generation, and drawn (purchased) from the grid when the generation is absent or insufficient to meet the demand. Sadly, in Nepal, we don't have any regulation allowing individuals sell power back to the electricity authority in this manner.

PV, an environmentally friendly and renewable energy generation technology, is considered very promising in supplying a significant portion the future electricity demand. In 2007, about 4GW of PV panels were produced worldwide, and the cumulative production was more than 12 GW. By 2010, PV is expected to generate about 35 GW of electricity (source: PV status report 2008, Joint Research Center, European Commission).

There are basically two kinds of PV installations. One is the isolated system, in which the PV generator is not connected to the local or national network, and is the only source of electricity to supply the target load. All PV systems in Nepal fall into this category. In such systems, a storage system, consisting of rechargeable batteries, is needed to provide electricity during non-shiny hours. The storage requirement increases the system cost, as well as makes it difficult to realize large-scale generation. The other is the grid-connected system. Almost all residential as well as large-scale PV systems worldwide, covering about 90% of the total PV generation, fall into this category. Large PV installations feed the generated electricity directly into the local or national supply network. In the case of grid-connected solar homes, power is fed (sold) to the grid when there is a surplus generation, and drawn (purchased) from the grid when the generation is absent or insufficient to meet the demand. Sadly, in Nepal, we don't have any regulation allowing individuals sell power back to the electricity authority in this manner.

Can solar electricity be a solution to Nepal's energy problem?

A basic 120 W solar system in Nepal currently costs about Rs. 125,000 ($1,600). Considering the system life of 25 years, and 5 hours of daily sunny hours, its electricity would cost about Rs. 23 per kWh, which is much higher than what we are currently paying to the NEA.

There is no doubt that PV is an attractive source of electricity for many remote villages in Nepal, and thousands of houses are already enjoying this clean energy. In many cases, electrifying a village by PV is cheaper than extending the grid (by the way, the grid in the current situation is almost useless). But, can it be a long-term solution to our ever-increasing power crisis?

The most serious problem with PV generation is its high cost at present. A basic 120 W solar system in Nepal currently costs about Rs. 125,000 ($1,600). Considering the system life of 25 years, and 5 hours of daily sunny hours (“peak suns”), its electricity would cost about Rs. 23 per kWh, which is much higher than what we are currently paying to the Nepal Electricity Authority (NEA).

The high initial cost of a PV system is set to decrease significantly over the coming years, as a large number of industries as well as governments in many developed countries are actively engaged in R&D to lower the energy cost of PV generation as well as expand its penetration. The Japanese PV roadmap aims to reduce the PV electricity cost to the residential tariff level (23 Yen/kWh) by 2010, industrial tariff level (14 Yen/kWh) by 2020, and a highly competitive level for high scale generation (7 Yen/kWh) by 2030 (source: PV roadmap 2030, New Energy and Industrial Technology Development Organization/NEDO).

In Nepal's current situation of power chaos, can PV be utilized as a solution? Well, different locales have different potential energy sources including PV, and we should compare their economical, technical as well as environmental aspects. Nonetheless, those who can afford PV system, even in urban areas, can enjoy its much more reliable electricity than the current grid supply, and thereby also contribute to improve the reliability of the grid by somewhat relieving its burden.

As for the government and the NEA, they should make suitable rules to allow the grid connection of residential PV systems. It not only eliminates the need for expensive batteries, but also effectively creates a distributed generating system. Along with a subsidy program, a large-scale adoption of PV is possible. As mentioned earlier, this is the most popular PV system in the world. For example, In Japan, out of 1.9 GW of PV installations, 1.6 GW is the grid-connected residential buildings (source: H. Matsukawa, PV Seminar, 2007). There is no reason why we are not yet allowed to use it in Nepal.

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11
Comments:

Does the cost of $1,600 (for 25 years of life span) include the cost of scheduled maintenance?

I am still for that cost, if expanding national grids require much more cost and time frame.

I believe the biggest drawback of PV is it's efficiency, even if we can overcome the cost of installation, we still need to overcome the availability of space to lay those cells (we need to monetize the aesthetic value of the landscape too) for bigger production of energy.

However, I am optimistic that technology is always improving and we can have better productivity. I recently saw in TV about few scientists in Univ. of California Berkley already coming up with more efficient cells.

Rameshji how are you?Thank you for your informative post.I also like to add that instead of installing the thermal plat government should act to subsidize more on PV. With PV there are still many thing to do though..like1) need of dedicated storage device like battery (which, however, is enviroonmental polluting).. Few sunny hours and many cloudy days are there2)Low efficiency of PV module.(the current commercial efficieny 15%?)Technology is getting matured. In future PV will be the most dominated power source for the plant.

Boga, Hiroshima
said...

I have been, at leat fro some time now, following the discussions on this blog. It is clear that the well-learned contributors to this blog (especially Nepalese) are well grounded with the problems facing their country; socially, economically or politically. tHe debates on power "failure" or "problem" seems to be well-know to you guys, including the current author. But the problem with our leaders (politicians)in developing countries is that they do not take academicians/experts seriously, more especially, if you are a citizen. in fact, they prefer outsiders, the so-called "experts". But fro you Nepalese guys out there, i am really impressed by you analytic views, and tenative solution to the power problem. Of course, funding could be a major setback, but you guys need to directly sell some of these good ideas to the Government.I want to confess that I hardly understand "power system" issues, but with intimate discussions with Deependra, I had learnt a lot about the problems faced by Nepal. To Dr. Bhandari, I want to thank you for this informative article.

Ramesh ji,Thanks for an simple and elaborate article on Solar PV Systems. Government policy of subsidizing Solar PV Systems in rural areas of in Nepal not served by national grid(I agree with you that grid has been rendered useless because of long hours of supply outages)should continue and better and more efficient service should be made available. In long run need for higher supply reliability and increase in demand will mean there has to be some sort of grid (it can be localized grid of generators based on different energy sources) to address these issues. But in short and medium terms, Solar PV Systems seem to be attractive. In future with expected reduction in cots of these systems, they can become an integral part of future power systems. In case of Nepal, with honest and competent leadership at concerned ministry and executing organization, the cost of Solar PV Systems can be brought down by at least 15-20% if not more. But can we expect the same to happen in our country?

Anonymous
said...

My friend, gone are the days when solar panels were able to convert only about 20% of sunlight to electricity. recently, the Defense Advanced Research Projects Agency, DARPA, has announced last summer that it has achieved 42.8% conversion efficiency. And now some nuclear engineers claim to have invented a new kind of solar cell that has a conversion efficiency of 60%!

The battery efficiency is too improving which is equally important to have an overall efficient solar PV system. So expect major breakthrough in solar PV system application in future. However, the solar systems might not be able to replace the other existing technologies of electricity fully. As there are many concerns other than the cost that questions the suitability of solar PV systems.

I am thankful to all of you for kindly reading the post and for encouraging remarks and comments. And I am grateful to Deependra ji for providing me an opportunity to reach out to the readers. As many of you have noted, cost reduction, performance improvement and long-term vision and policy are required for wide-scale adoption of PV technology.

Dear Kamaladi.com, the cost that I mentioned is a rough estimate, based only on the initial investment. Yes, low efficiencies and consequently large areas of PV panels is one concern, but if it becomes cheap enough, it would not be a problem, at least for residential rooftops.

Dear Netra, I am fine, thanks. You are right that dedicated storage is a limitation of off-grid solar pv systems. But in urban areas batteries are not required if the NEA allows grid-connection, as in the other countries.

Dear Boga, thanks for your comments. We would not be facing most of the current problems, had our govenrment and politicians good vision and policy.

Dear Nava Raj sir, I agree with you that the PV can be an integral part of our future power systems. I have high hopes for grid-connected “solar houses” rather than large-scale PV power stations. Small investments from individuals to “solarify” their houses, along with a proper support from the government, will create a large power generator in effect.

Dear Anonymous, thanks for sharing the news about high efficiency solar cells. First, let's hope that we will have a 20% efficient solar panel in the near future. The current highest efficiency of commercial PV panels is about 17% (Sanyo), and the efficiencies of mainstream panels are around 10%. As far as the 42.8% efficient DAPRA cell concerned, it belongs to the group of so-called multi-junction solar cells, which are much more expensive than the ordinary “single-junction” solar cells, and are utilized in space, military, and “concentrated” solar pv applications. Any way, it would be very nice if and when these laboratory-scale high-efficiency cells are commercialized and available at low costs. I did not know that a 60% efficient cell was realized. Could you please provide me a link?

Dr. Bhandari, Thank you very much for the simple and easy to understand description about solar pv, the ultimate source of energy in the green planet. I have gone through financial analysis of your description and even if you are not using the maintenance cost, cost of energy per kWh seems be higher than mentioned. May be higher than Rs 50/ kwh, depending upon the efficiency of of the system (battery chrging and idscharging), number of black days and like that. Anyway I liked your paper.

We'd love to have an analysis Rameshji of the total unit cost of solar generated power if the batteries were to be removed and the system adapted to Nepali conditions. How much of a difference will that make to the Rs. 23/KWh you mentioned earlier.

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Deependra Kumar Jha

...an educationist who holds a doctorate degree in electrical engineering...loves writing and views blogging as a wonderful medium to express the essence of things...writes when moved by intense passion on various themes, subjects and issues...his write-up emphasizes on the virtues of perseverance and optimism...

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